Creates a new image and a command with the same name and returns its name.
type specifies the type of the image, which must be one of
the types currently defined (e.g., bitmap).
name specifies the name for the image; if it is omitted then
Tk picks a name of the form imagex, where x is
an integer.
There may be any number of option-value pairs,
which provide configuration options for the new image.
The legal set of options is defined separately for each image
type; see below for details on the options for built-in image types.
If an image already exists by the given name then it is replaced
with the new image and any instances of that image will redisplay
with the new contents.
It is important to note that the image command will silently overwrite any
procedure that may currently be defined by the given name, so choose the
name wisely. It is recommended to use a separate namespace for image names
(e.g., ::img::logo, ::img::large).

Deletes each of the named images and returns an empty string.
If there are instances of the images displayed in widgets,
the images will not actually be deleted until all of the instances
are released.
However, the association between the instances and the image
manager will be dropped.
Existing instances will retain their sizes but redisplay as
empty areas.
If a deleted image is recreated with another call to image create,
the existing instances will use the new image.